VOD冶炼超纯铁素体不锈钢的脱氮研究

分析了VOD冶炼超纯铁素体不锈钢过程的脱氮热力学和动力学,得出其脱氮反应接近二级反应,可用Δ(1/wN])来表示脱氮效果。用前期开发的脱氮模型计算并分析了VOD的脱氮过程,在VOD吹氧脱碳阶段,脱氮效果Δ(1/wN])与脱碳量ΔwC]成正比,可用脱氮指数Δ(1/wN])/ΔwC]来表征此阶段的脱氮能力,铬含量为11.6%、17.6%及20.5%的钢液脱氮指数计算值分别为208%-2、109%-2及81%-2,实际生产数据分析得出的对应的脱氮指数略高于计算值,而在VOD自由脱碳阶段,Δ(1/wN])随时间变化的计算曲线基本不受初始氮含量的影响,温度是影响脱氮的主要因素。

Denitrogenation study in the VOD process for ultra clean ferritic stainless steel

This paper analyzes the thermodynamics and kinetics of denitrogenation in the vacuum oxygen decarburization （VOD） process for ultra clean ferritic stainless steel. The denitrogenation process can be calculated with a denitrogenation model developed at the earlier stage. It is concluded that the denitrogenation process can be regarded as a second order reaction and the denitrogenation amount should be expressed in terms of A（ 1~wEN~ ）. It can be illustrated that the A（ 1/wN] ） is proportional to the decarburization amount Awc] at the oxygen blowing stage of VOD. The denitrogenation index defined as the ratio of A （ 1/WN] ） to Awc] can be used to evaluate the denitrogenation ability at that stage. The denitrogenation indexes for the treatment of the steel melts with 11.6%, 17.6% and 20.5% chromium contents at the stage are calculated as 208% -2, 109% -2and 81% -2, respectively. The denitrogenation indexes worked out based on the actual VOD data are a bit higher than the calculated values. At the free decarburization stage, the calculated curve of A（1/WN] ） that varied with time are almost independent on the initial nitrogen content. The denitrogenation effect is affected mainly by the temperature.